Posts Tagged ‘mounting shocks for the C4 Corvette IFS’

The C4 Corvette suspension that I removed form the 1986 Corvette Indy Pace car convertible has found a new home in the 1929 Ford Model A hot rod. Everything is just about complete on the hot rod chassis. My first attempt at designing and developing an upper shock mount for the coil over shocks just did not impress me. I felt the design was too bulky and awkward looking. Simply said, it was not a clean design. I am the sort of person that if I am not pleased with something, especially something I built, I need to fix it or I will always regret it if I don’t. With those thoughts in my mind, I decided to cut the upper coil over shock mounts from the chassis. Of course, this was no easy task. When I put something together, I tend to do it well. With the heavy welds around the entire shock mount, I was grinding for some time. After a few hours, I manage to remove the upper coil over shock mounts and nicely clean up the chassis. Now I was ready for a second attempt at this.

1929 Ford Hot Rod front coil over shock mount - view 1 - this was my first version of the upper coil over shock mount. A shock from the rear suspension of a Jaguar XJ-12 was used. It was the correct length and also seems to have the correct spring rate.

1929 Ford Hot Rod front coil over shock mount - view 2 - The upper mount just did not have the right look for me so it was removed.

1929 Ford Hot Rod - Jaguar coil over shock - This shock has about 13.5 inch distance between mounting hole centers and is a perfect size to use on the front suspension of my hot rod.

Originally I had a Jaguar independent rear end that came with four coil over shocks. I sold the rear end and kept the coil over shocks. This was part of the package that came with the 1931 Ford Model A 5 window coupe I previously purchased and sold. I found that these shocks had a perfect distance between the mounting holes and seemed to have the correct spring rate for the front of my 1929 Ford Model A hot rod. My intention is to use these coil over shocks temporally till I generated more funds for some nice chrome or aluminum coil over shocks.

1929 Ford Hot Rod - front lower coil over shock mount - version 1 - this is one possible mount that I am thinking of using, but still not sure.

1929 Ford Hot Rod - front lower coil over shock mount - version 2 - this another mount up for consideration and is the same as the lower mount I used on the rear shocks of my hot rod. I am leaning towards this style, but made out of stainless steel instead. Eventually, I intend to polish all of the aluminum suspension parts, have chrome coil over shocks, so this style of mount using stainless steel makes a bit of sense.

The lower shock mount is basic. I used a triangle pattern for the base of the shock mount. A couple of half moon shaped brackets were welded to the base of the lower shock mount. All of these pieces where fabricated from 0.25 inch steel plate and cut out on my metal cutting band saw. To make sure for a perfect fit, I bolted the half moon brackets to the shock, and then positioned the shock with brackets onto the lower shock mount base. This was then tack welded in place. Once I was happy with the position and fit of the shock, the half moon brackets were permanently welded in place. This assembly fits perfectly into the lower control arm from the C4 Corvette. Another consideration for the lower shock mount is to fabricate one from 2 inch stainless stain square tubing and using small spacers inside to make up the difference between the width of the shock mount and the opening of the bracket. I am leaning more towards this style considering that I will eventually polish all of the aluminum suspension parts and use chrome coil over shocks.

1929 Ford Hot Rod front coil over shock mount - view 3 - I discovered that if I angled the shock in more towards the frame and directly under the upper control arm that my spring rate was not effected by much.

1929 Ford Hot Rod front coil over shock mount - view 4 - A set of new upper shock mounts were made from 0.25 inch plate steel. A always a template was created just in case I ever wanted to make more of these brackets.

With the lower shock mount placed onto the lower control arm, I started to examine various mounting options for the upper shock mount. Very quickly I realized that I could create a much smaller mount just under the mounting bar of the upper control arm from the C4 Corvette. The only concern I had was that the angle of the shock was increasing slightly. The correction factor when mounting shocks on a 15 degree angle is 0.93 and for a 20 degree mounting angle is 0.88. This is approximately the change I wanted to introduce to the suspension. So to check things out, I was able to set the upper shock mount temporarily. I added a few sand bags as extra weight or ballast to compensate for parts still not on the chassis. Then I positioned my 250 pounds onto the chassis. I took a resting position measurement and another one when I started to bounce up and down on the chassis. This activity resulted in only a 1 inch movement in the suspension at the best of times. This seems reasonable to me so I then decided to create a second version of the upper shock mount. Once again to ensure a perfect fit, I bolted the newly fabricated upper shock mounts to the shocks. The complete coil over shock assembly was then fitted to the chassis. With everything in place, the upper shock mounts were tack welded to the chassis. Making sure that this was what I wanted this time and that the mounting positions were correct, I removed the upper control arm and shock for the final welding process of the upper mount.

1929 Ford Hot Rod front coil over shock mount - view 5 - The new brackets were bolted to the upper mount of the coil over shock. With everything in place, the new mounts were tack welded to the frame.

1929 Ford Hot Rod front coil over shock mount - view 6 - Everything looked as it should, my spring rate was not reduced my much with the increased angle of the coil over shock.

1929 Ford Hot Rod front coil over shock mount - view 8 - This is the finished and primed result of my efforts. I think this doesn't look too bad.

1929 Ford Hot Rod front coil over shock mount - view 9 - The front suspension is painted for now and mounted back onto the frame. Later on I intend to purchase a nice set of polished coil over shocks to replace the 1 inch square tube.

Standing back and looking at the new version of the upper shock mount, I felt the entire process was well worth the time and effort. In my mind the design was much cleaner looking. This outcome is in line with my over all goal with this project. It is to build a good looking, safe, and, have great handling characteristics hot rod with a minimum of expense. So far, I am right on track.